Hosta plantaginea -- &#34;Gold Margin&#34; variety

ABSTRACT

A new variety of Hosta plastaginea characterized by a gold to lime green margin on a darker green leaf and a thicker, more rigid, and more coriaceous leaf structure, giving the plant a more upright habit than the original species.

SUMMARY BACKGROUND, AND ORIGIN OF THE INVENTION

The new variety is a tissue culture derived sport of the species Hostaplantaginea. I discovered the plant in a cultured state in a greenhouseon the premises of Walters Gardens, Inc., Zeeland, Mich., among a groupof transplanted propagules produced from a plant tissue culturelaboratory. The stock plant was from Hosta plantaginea which had begunproducing mutant sports of a mixture of variegations including those ofa sectorial, mericlinal and periclinal nature. A single plant with astable periclinal variegation was noticed in the summer of 1988 and wasseparated from the rest of the transplants. Continued observations ledto a greater recognition of the uniqueness of the plant.

The cultivar has been asexually propagated via tissue culture at anursery in Zeeland, Mich. It has also been asexually propagated bydivision of the rhizome. Although tissue culture propagation can produceaberrants or mutants, making some culling necessary, to one skilled inthe art of tissue culture it can also be a propagation tool useful inproducing identical plants.

By using the method developed and improved at a nursery in Zeeland,Mich., the Hosta `Gold Margin` variety is being successfully propagatedso as to produce plants that are substantially identical to the originalplant by tissue culture division as well as by garden division of therhizome.

The new variety is hereby named "Gold Margin" and is sold under thetrademark "Heaven Scent".

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is illustrated in the attached photographic drawings inwhich FIG. 1 shows the plant from a perspective above the plant and FIG.2 shows the plant from a side elevational perspective.

Botanical Description of the Plant

Hotas plantaginea is a densely rhizomatous herbaceous perennial with ashort subterranean stem and petioled, tufted leaves. The glossy surfacedleaves are ovate to cordate-ovate and have nine (9) to eleven (11) veinpairs and are a uniform dark green in color, essentially the same coloras the dark green central portions of the leaves of the presentinvention. Leaf dimensions are approximately nine and one-half (91/2)inches to ten (10) inches long and six and one half (61/2) inches toseven (7) inches wide. Foliage height is approximately twenty (20)inches to twenty-four (24) inches and bears twenty-six (26) to thirty(30) white fragrant funnelform flowers, each three (3) to five (5)inches long, on a thirty (30) inch capitate raceme or rarely panicle.The dimensional and flower number are dependent on environmentalconditions and cultural practices, and therefore may be slightly greateror smaller. The flowers bloom in Michigan from mid-August tomid-September. Flower characteristics and fragrance are identical tothose of the parent species.

The species Hosta plantaginea is quite uniform in appearance and doesnot have a large number of varieties or subspecies. The principal formof the plant is generally known by the species name Hosta plantaginea.Some variants that have been developed have been given distinct varietynames. There appear to be two forms of the principal species that iscalled Hosta plataginea. These appear the same and are differentiatedonly by the size of the flower. One size is considered to be the normalor average form and the other is considered to be larger than normal.The present invention was derived from the normal form of the speciesknown as Hosta plantaginea.

Hosta plantaginea is one of only two species of this genus that arenative to, and only to, the mainland of China. The other species, Hostaventricosa, flowers much before Hosta plantaginea, thus preventing anylikelihood of interspecific cross pollination. All other speciesdiscovered to date have come from either the islands of Japan or a fewfrom those of Korea. Being so geographically isolated, an intrabreedingspecies population will tend to become more identical.

Hosta plantaginea also has many traits consistent with a plant of atetraploid nature (having twice the normal compliment of chromosomes). Anatural doubling of the chromosomes would tend to produce a morehomozygous population resulting in nearly identical appearingindividuals.

The new variety shares the foregoing characteristics with its parent,but is a unique and improved form of the original plant species, Hostaplantaginea, in two principal aspects. First, the new variety is adistinct and stable chimera with a lighter yellowish margin and a greencentral portion of the leaves. The second distinction is that of animproved substance or increased thickness of the leaves.

The variegation in the plant varies in color from spring through autumn.As the leaves emerge in the spring, the color difference between themargin and the center of the leaf is barely discernable. The margincolor proceeds to lighten as the growing season progresses, and bymid-summer with the plant grown in the proper shade, the margin color ismore grey than Sap Green 62 as defined by The Royal Horticultural ColourChart and more yellow than Pod Green 061. The leaf center is slightlydarker than Scheeles Green 860 or about 960. An intermediate color, aScheeles Green 860/2, is frequently exhibited at a position between themargin and center of the leaf. This is the result of a type oflamination of cell layers with differing amounts of pigment coming fromtwo distinct histogenic regions of the meristem.

The margin tissue generates from the outer layer of the meristem usuallyreferred to as the L-1 layer. The inside portion of the leaves iscomprised of the second layer in the meristematic dome, usually calledthe L-2 layer. When the leaf primordia is developing, some regionseither of the L-1 or L-2 may grow faster than the corresponding region,producing a section of the leaf with either a wider margin or enlargedcenter. Likewise, when the meristem layers occupy the same location(between the margin and the center) the L-1 layer determines the surfaceof the leaf, either the adaxial, abaxial, or both, and the L-2 producesthe medial portion of the leaf. This inconsistent development of themeristematic, or histogenic, regions tends to produce the typicallacerated effect of the margin, the varying widths, and also the normalbut irregular evidence of the intermediate colors.

When grown in more sun or higher light intensity, the margin inmid-summer is a Sulfur Yellow 1/3, and the center is Lettuce Green 661.

The margin variegation, although stable, is uniformly irregular andfrequently protrudes toward the midrib. The width of the margin variesin measure from very thin on an immature plant to an irregularthree-eighths (3/8) inches to three-quarters (3/4) inches or more on amature specimen. A young plant may have thin margins on the first leavesand develop wider margins on the older leaves of those produced later inthe season. The leaves produced later in the season tend to be moretypical of the mature version.

Environmental conditions, cultural practices, and growth rate alsoaffect the extent, color, and width of the margin.

Typical of plants in the genus Hosta, the petiole is more like anextension or modification of the leaf. As such, it has the samevariegation with a few minor variations. The petiole is more protectedfrom the sun and thus the lighter color darkens, or does not bleach asmuch. Also, because there is much less width for the variegation tospread out, the intermediate color is not present, and the jaggedness isnot visible.

A second distinctive characteristic of the new variety is an improvedsubstance or thickness of the leaves. While the original species has asoft, flexible, thin leaf that tends to droop or bend downward, thepresent cultivar is more rigid and stiff. The leaf of the presentvariety is thicker and more coriaceous than the original species. Thisgives the leaves a more upright habit than the original species, withthe leaves tending to extend more upwardly instead of bending ordrooping downwardly. The substance and leaf thickness of the parentspecies are the same as shown in applicant's co-pending application forthe White Margin variety (Ser. No. 540,816, filed Jun. 16, 1990), whichis incorporated by reference.

The growth of Hosta `Gold Margin` is essentially the same as that of theparent species, Hosta plantaginea. Mature height and size of the leavesis slightly reduced; however, vigor is not noticeably changed. Like theparent species, the plant grows better with ample water, but anestablished specimen can withstand some brief periods of drought.Flowering is more prolific with more sun, but in Zeeland, Mich. growthis best with light shade during the hottest part of the day. The plantis resistant to most diseases and can survive sub-zero temperature. Thefoliage is not frost hardy and can be affected by late spring frosts.All other aspects of the plant including flowering and seed productionare identical to the parent species.

I claim:
 1. The new and unique variety of the plant Hosta plantaginea,substantially as described and illustrated.